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Comment by boplicity | Hacker News Reader

I've grown increasingly skeptical of carbon removal. It strikes me as incredibly inefficient; there are much easier and cheaper gains to be made by no longer removing carbon from the ground in the first place.

Further: The Carbon Removed website claims that carbon is "permanently" removed from the atmosphere, and yet lists some of the carbon removal sources as "reforestation." This doesn't add up. Forests are part of the carbon cycle, and not a way to "permanently remove" carbon from the atmosphere.

Overall, I very much doubt that our society will do enough to stop climate change from drastically changing our planet. I wish that I saw initiatives like this as a source of hope, but don't see much, if any evidence to support such hope.

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Yeah I don't buy carbon removal as a practical solution. Humanity spent over 100 years pulling concentrated carbon out of the ground as fast as we could and got a bunch of useful energy out of it. Now all that carbon we pulled out of the ground and dumped into the atmosphere is a stable trace gas. The thermodynamic hurdle to reverse what we've done is huge. The thermodynamics is not there, the economics is not there.

To be fair, we have never been more efficient at extracting carbon from the ground than now. The first 150 years we were terrible compared to today.

30 more years at this rate will double our total CO2 emissions.

We've already created a problem, but a small one compared to what will happen if we don't stop soon.

On the flip side, we're just starting the 100 years now trying to extract carbon dioxide out of the air as fast as we can to get a livable planet out of it.

Granted we (as a species) have huge challenges ahead of us, but with collective effort it could be possible.

Our CO2 output is increasing. Under the world's current political/economic regime, we can't keep our CO2 output stable, let alone decrease it. If we lack the seriousness to do that, we definitely lack the ability to do the much harder task of removing what we've already put there.

Keep in mind that the energy expended in C02 sequestration is concentration. It's easily soluble in water when injected and then is reactive to produce mineral precipitates. And that's only the geologic sequestration. There are multiple approaches, both biological, engineered, and geologic. Either way, the hard part is going from dispersed to concentrated in most cases (or for the biologic cases, actually keeping the result in the biosphere and not decaying into the atmosphere).

You don't need to reverse the combustion reaction.

You don't have to spend anywhere near as much energy as you gained from combustion to sequester it. You're not turning it back into bare carbon or into a hydrocarbon.

You're breaking hydrogen - carbon bonds to gain energy during combustion. You're then sequestering C02 -- you don't need to chemically alter the C02. You do need to concentrate it, but in terms of thermodynamics, you get a large amount of energy from combustion and it takes less than that to concentrate the combustion products.

In principle (but often not reality to the practicalities of concentrating a dispersed gas) combustion and then sequestration can be energy positive overall. The thermodynamics isn't quite what folks often assume.

Carbon removal is definitely not mututally exclusive to reducing emissions in the first place. Avoiding emissions is cheaper and easier than removing them. But realistically we can't stop emitting tomorrow and even if we could, we have an excess of emissions in the atmosphere to address.

As for hope, it's a mixed message. On one hand we have more emissions than ever. On the other we have more awareness and action than ever. Personally I lean towards hope and want to give it as much of a chance as possible.

We see net-zero as a bridge to a more sustainable future. Reduce emissions and remove the unavoidable.

You may see a tree as an ephemeral carbon storage, but the forest is a much, much long term storage, that can be considered permanent (unless catastrophic fire).

The forest, at each time point, contains many trees, growing ones, dying ones, decomposing ones, seeds, etc. But its overall solid carbon mass is strictly positive and larger than, say, a meadow, and if you have the right conditions it can be slowly growing year after year.

So planting trees is a way to store carbon, just not to be thought at the tree scale, more like at the forest scale.

Edit: a lot of carbon is stored in the soil, too, especially in the thick humus of a healthy forest. Even if each individual component of the humus is decaying, disappearing and replaced by new fallen leaves etc, the humus layer itself is not going anywhere.

It’s been a bit since I did a deep dive on this (thanks AirMiners), but my understanding is that we have to get to net zero and sequester large amounts of carbon currently in the atmosphere to avoid some of the worse climate scenarios. It’s not either/or. We’re past the point where cutting to 0 in a decade or two yields acceptable outcomes. But to your point, sequestration is much more expensive than reduction, so cutting down new emissions is going to have to be the vast majority of the reduction.

And yeah, forestry credits are really fraught with problems, but they’re much, much cheaper than real sequestration, which is why stuff like this always offers them. There is some time-value of sequestration in the short term, though.

Yup, the latest IPCC report relies heavily on carbon capture in a lot of the predicted 'limitation' scenarios.

We do not see carbon removal as an excuse to continue polluting or not reduce emissions. It's a "both" situation and we go even further to say we need many different kinds of removal as there isn't a "silver bullet" that will solve decades of burning fossil fuels.

These will involve natural and technological methods to restore a bit of stability to the climate.

There is only one way to permanently remove carbon from the atmosphere, and that's to launch it off the earth and onto a path where it could never make it back. Everything else will store carbon for a while, before eventually releasing it again

A forest stores lots of carbon while it exists - there's cycles of trees dying and releasing carbon, and new trees taking their place absorbing carbon, but there is a steady state change in terms of carbon in the trees that currently exist. The carbon is only released by deforesting the area again

There are many things between forest and space launch. If you inject the CO2 underground at a reasonable rate, you can get it to bind to rock, chemically changing that rock. It might eventually find its way back to the atmosphere, but on geological timescales. If you sink kelp to the bottom of the ocean, that also effectively sequesters it.

Given the existing headwinds I am skeptical we can make any progress without removal. The problems are a two hit combo of political will and technical limitations.

I suspect that the end goal with this carbon credits scheme is almost entirely control and surveillance. The effectiveness of the stated intent doesn't matter from that perspective. Once the system is in place, then it is gradually expanded to the individual level and someone has to keep tabs on everyone's credit balances after all. Think KYC but for everything but a bit worse. Good luck ;)

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